"Nevada is a blue-leaning state where the President is likely to do well and where Republicans like Dean HellerDean Arthur HellerSenate GOP wary of new tax cut sequel GOP Senate hopefuls race to catch up with Dems Family, friends mourn death of Barbara Bush MORE have a very hard time appealing to the growing number of Hispanic voters," DSCC Executive Director Guy Cecil said in a statement. "Dean Heller is particularly vulnerable, having said he was proud to vote twice to end Medicare and calling for Nevada to implement an Arizona-style immigration law. Shelley Berkley is a proven fighter for Nevadans and we are ready to win this race."

The committee has long been involved in the race — their first ad buy of the cycle was a Spanish-language ad attacking Heller — and is unlikely to walk away from what has until now been a coin-flip race in the polls. But their need to prove they're standing by Berkley shows how potentially damaging the investigation could be to her campaign.

The Hill currently rates this race a "toss-up."